Modern refrigerator/freezers often include an ice dispenser for dispensing ice pieces formed in the freezer compartments into a discharge station on the exterior of the freezer door.
Typically the ice dispenser includes a motor and a motor control circuit. The motor control circuit is actuated by an ice command switch located at the discharge station. The ice command switch is actuated by a glass or other container placed against the switch, causing the motor to rotate and deliver a desired quantity of the ice pieces into the glass.
One such ice dispensing apparatus is disclosed in pending Linstromberg et al, U.S. patent application Ser. No. 747,890, filed June 24, 1985, entitled "Ice Dispensing Apparatus", and assigned to Whirlpool Corporation, assignee of the instant application.
According to Linstromberg et al, actuation of a switch energizes an analog timing circuit coupled to a triac. Upon actuation of the switch, the timing circuit turns on the triac, allowing current to flow through a motor connected in series with the triac.
The timing circuit includes an RC network. Upon actuation of the switch, the capacitor of the RC network begins to charge. When the capacitor has charged to a predetermined level, the timing circuit turns off the triac, preventing flow of current through the motor and hence stopping it and delivery of ice pieces. The RC circuit includes a selectively variable resistor for a variable capacitor charge time, resulting in a selective motor rotation time.
However, according to Linstromberg et al, the ice start switch must operate at the same high potential as the motor. Further, a conductor handling a high voltage and high current must traverse the joint between the freezer door and the freezer compartment.